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(No Model.) 2 Sheets-Sheet 1. W. B. PRALL, Jr.

STREET GAR MOTOR.

No. 426,061. Patelg te Apr. 22, 1890.

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(No Model.) 2 Sheets-Sheet 2. W. E. PRALL, Jr. STREET GAR MOTOR. No. 426,061. Patented Apr. 22, 1890.

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WITNESSES '1, lNiTED STATES PATENT OFFICE.

\VILLIAM E. PRALL, JR, OF \VASI'IINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO THE PRALL TRAMVVAY MOTOR COMPANY.

STREET-CAR MOTOR.

SPECIFICATION forming part Of Letters Patent No. 426,061, dated April 22, 1890.

Application filed December 30, 1889. Serial No. 335,3. (No model.)

T at whom it may concern:

Be it known that 1, WILLIAM E. PRALL, J r., a citizen of the United States, residing at \Vashington, in the District of Columbia, have invented certain new and useful Improvements in Street-Oar Motors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of the invention is to simplify the construction and increase the efficiency of steam-motor apparatus for streetcars; and it consists in the devices and combinations hereinafter described and pointed out.

In the accompanying drawings, Figure 1 represents a side elevation, partly in section, of a street-car and apparatus for moving the same. Fig. 2 is a sectional plan showing the connection of the engine with the movinggear; and Fig. 3 is a plan of the steam-generator coil, the burner and inclosing-case being in horizontal section.

1 1 indicate I-beams secured to brackets 2,

2 5 which embrace axles 3, which latter are connected to and support the car-body upon the main wheels in any approved manner.

1 denotes a water-reservoir, preferably protected against radiation of heat by a noncon- 0 ducting covering and supported in any convenient manner, as by the brackets 5, of which there are two, one being secured to each of the beams 1, as indicated. This reservoir communicates by pipe 6 with a generator, con- 3 5 sistin g, as represented in the present instance, of a pipe-coil 7, suitably disposed within a combustion-chamber 8 and over or about a perforated burner-cylinder 9. Liquid, gaseous, or vaporized fuel is supplied through a pipe 10, having cook 17 and communicating with a source of supply, as an oil-tank 11, which may be conveniently located on the top of the car. The upper end of the steamgenerator (represented in the present instance 5 by a coil, preferably made of copper pipe) communicates, by means of pipe 11, with the valve-chest 12 of a steam-engine 13, supported 011 the beams 1, or in any approved manner.

14: is an exhaust-pipe leading to a series of condensers 15, which have communication with the open air, and preferably above the car.

16 is a valve or cook for closing the steampipe, and 18 a second valve in said pipe. Between the two latter valves is a branch steam-pipe 19, leading back and connecting with a coil in the water-tank, and continued thence back again to and connected with steam-pipe 11 at a point between valve 18 and the engine. The water-tank is situated at about the same level as the generator and connected with the bottom thereof by an ordinary pipe, and the generator is also formed of convolutions or coils of pipe rising near to or above the highest level in the tank. This construction, combined with the herein-described devices for controlling the fire and regulating the discharge of steam, one or both, allows a free communication between generator and tank during the production of steam without danger of high pressure, and provides for a method of operation, which consists in conducting water into the bottom of p the generator continuously, except when it is prevented by the backward pressure of steam returning surplus steam to a heating-pipe in the tank and automatically shutting off the steam-supply when a steam-pressure above a described limit is reached.

The steam-space of the generator is provided with a branch to lead to a diaphragmchamber, forming a part of an automatic valve-operating apparatus of well-known construction, connected with the fuel supply 8 5 pipe. The water-supply pipe (3 is furnished with a valve or stop-cock 20.

The operation of the above-described devices is as follows: Oil and water being supplied to their respective tanks or receptacles, the valves 16 and 20 are opened, and the fuel issuing from pipe 10 at its end within the burner is ignited, air being freely admitted to promote combustion, and the products of combustion, after circulating about the coils 9; or other ports of the generator, escape through a suitable exit-pipe, as 21. Steam is thereby generated and then conducted to the engine to drive the same in the usual manner.

The pipe 11, provided with a cutoff cock r00 17 or 18, may be used to conduct steam direct to the engine. It is also contemplated by the invention that steam may be conducted by a pipe 19, 1eading to the water-tank and thence to the engine, a cock such asv either 22 or 23 being used as a cut-oif. In the construction shown the closing of cook 18 provides for thus conveying the steam to the tank and thence to the engine. For this single purpose, however, the portion of pipe between the extremities of pipe 19 might be permanently closed or entirely removed, and pipe 19 thus adopted as a means of communication from the generator to the engine by Way of the tank. The construction illustrated is, however, preferred, as by it steam may be supplied either directly or indirectly to the engine, or by suitably regulating the cooks shown a part can be sent direct to the engine and a part by the way of the tank.

It is one of the objects of the invention to keep the water in the supply-tank hot by the circulation described. The heat of the generator may also be maintained by the burner, and steam can be instantaneously generated at will by admitting heated water into the highly-heated coil generator by simply opening the steam-cut-oif cock, and thus reducing the back-pressure in the generator and permitting water to enter it; and it is one of the important features of the improvement that the generator-coil shall be capable of storing a large amount of heat and transferring it quickly to the Water entering the same, and also that this supply of water shall be automatically regulated by the pressure therein.

The'automatic regulation of the fuel-supply, the thorough and noiseless condensation of exhaust-steam by perforated condensers or their equivalent, and the convenient and efficient control of the cut-off cocks in the fuel and steam supply pipes by the use of the braking apparatus are also important features in the relations pointed out. I

The cocks can be connected to be operated from any desired part of the car. As, for example, cocks 16 and 17 may be connected by 'means of cranks to a rod leading to the platform and loosely joined to one arm of a bellcrank lever, the other being arranged in the path of thearm 30, fixed on a brake-rod 31. As represented, this rod is made movable vertically in brackets connected to the car, and is provided with a screw-threaded connection with a socket in a bracket in such manner that it can be lowered to carry the projection 30 against the. horizontal arm of the bellcrank lever to open the cocks, the open connection of the cooks being indicated in Fig. 1. On turning the screw-threaded rod in a reverse direction the arm or projection 30 is lifted from the bell-crank lever and the cocks are closed by a spring 32. The continued revolution of the rod after the closing of the cooks applies the brake 33 to the car-wheels by means of the connecting-rod 3a and chain 35, the latter being wound upon the foot of the rod in such manner as to draw the brake upon the surface of the wheels, the spring 36 being also at the same time compressed,which spring serves to release the brake from the wheels when the chain is unwound by a reverse movement of the rod 31.

It is characteristic of this part of my improvement that the brake and the cooks can be simultaneously operated from the car at will by the rods or well known equivalents, both to apply the brakes and open or close the cocks by the same manipulation, so that the brakeman suitably shuts off or opens the steam and fuel supply pipes by the braking operation.

The car-wheels can be geared to the engine by means of a gear 24, made fast to an axle and engaging a pinion 25, revolving on a bracket-stud and connected to a pulley 26, which pulley is geared to the engine by means of pulley 27 and a chain or cord 28, the pulley27 being connected to the engine in any usual or suitable way. The forward and rear car-wheelscan be geared together by chain wheels 27, as indicated.

It will be understood that the particular form and arrangement of the tanks, heatingcoils, steam-generator, combustion chamber, burner, gears, valve-rods, and brake-rod are not of the gist of the invention, except as hereinafter pointed out, as these can be varied by mechanical skill in many particulars without departure from the invention or from its principles of operation.

The particular means of operating the valves may be varied by extending the rod to other parts of the car and'by operating one or more valves by a single rod, which may or may not be the brake-rod, or other means than rods known in the art can be resorted to. In like manner equivalent forms can be adopted for the generator. It is, however, important that a large steam-generating surface be exposed to the products of combustion to secure prompt production of steam. It is also desirable that means be provided for maintaining the heat of the water in the tank and utilizing surplus steam for the purpose,'and all'parts'helding or conveying hot fluids may well be protected by non-conducting coverings. It will of course be understood that the fuel-supply pipe may at its outer end be provided, if desired, with any of the usual appliancessuch as a drippan, air-distributer, and damper and relighting-burner and also that a secondary airsupply may be provided, and it is not deemed necessary to describe and illustrate such matters. It will, however, be further understood that the above-described apparatus is suitable for propelling other vehicles than streetcars.

The water-tank is preferably located under the car, but not necessarily, and this is true also of the generator and engine. If the tank be at much higher level than the generator, it will in some cases be desirable to reduce the size of pipe 6 to check the flow of water to the generator. In such case if thepipe be too small for the ready return of the water to the tank by back-pressure an ordi naryby-pass pipe 37 with check-valve 38 maybe used. The pipe 6 may be provided with a cook 39, which will be convenient it found necessary to close the pipe in making repairs or for any reason, and obviously it can be used to regulate the amount of water allowed to flow through the pipe. It is according to the present improvement, however, to maintain an open connection between the generator and boiler, and to use pressure in the generator to prevent too large a supply of water. It is to be understood, however, that normally the pressure in the generator is insufficient to prevent the inflow of water, and that this inflow is totally prevented only when the generator-pressure is raised above a normal or workin g degree, as by continuing the fires after the steam-pipe has been closed.

Besides the uses named for cock 39 it could be used to entirely shut off the water-supply for the purpose of bringing the engine to rest; but preferably a cock for this purpose is provided in pipe 11, and it may be variously located therein or in modification thereof for some of the purposes of this invention. Thus it would be possible to direct all live steam through pipe 19 and use either cock 16, 22, or 23 to shut ofli' steam from the engine, and it is noted as coming within the invention that steam can be discharged into tank 5, in which case it may, if desired, be taken thence to the engine. Pipe 37, located back of the cut-off valve, will be used in this case, in order that pressure from the tank may be kept from the engine when said valve is closed. This pipe 37 is provided with a cook 38, and pipe 19 maybe provided with acheckvalve 39. Dotted extensions of parts of pipe 19 at the tank indicate a suitable arrangement for this operation.

The constant open condition of the pipe 6 adapts it to instantly supply water for production of steam when the relation of the pressure in the generator and tank is normal, and the construction of the generator, of pipe, or other like form, whereby its whole extent is thorougly exposed to the heat of the fire and the character of the fuel which adapts it to be instantaneously supplied and lighted or cut off, all combine to adapt the apparatus to the exigencies of street-car service; and the preferred construction, whereby the fuel and steam supply valves and the brake are all so connected as to be operated by one device of simple and familiar character, combined with the features above enumerated, further adapts the apparatus forstreet-cars and the like, and the means of noiselessly discharging either live or exhaust steam increase its fitness for the uses named. Such devices are not, however, claimed herein, except in the combinations pointed out. A like remark is applicable to other portions of the apparatussuch as the brake, for example-it being obvious that any wellknown forms and those applicable to both front and back wheels may be employed.

The burner-tube may be made of asbestus or of like material in any approved form, and its combustion-chamber may be of other form than rectangular, and its exit-pipe may have a branch or branches running through the car for heating purposes.

I am aware that the throttle-valve of an engine and brake mechanism have been so combined with a tripping device on a track that the steam could be shut 01f and the brake applied automatically, and I do not broadly claim devices for simul taneou sly shutting off steam and braking.

I am also aware that surplus steam has been used to heat feed-water, the steam-pipe opening into the air after passing through the water-tank. By my method no live steam is allowed to escape, which is a matter of spe-, cial importance in a streetcar.

I am further aware that a steam-generator has been supplied by an open conduit communicating with the water-tank, the water level of which was automatically maintained by a float. By my construction water is taken from below the water in the tank and the automatic regulation of the water supply to the tank dispensed with, and my tank is intended and adapted to hold hot water, and is a hot-water-pressure tank in open comm unication with the generator by means of a pipe having a small passage, whereby when the escape of steam through the engine is closed and the pressure raised sufliciently high in the generator it will force or hold back the water in the pipe. Upon admitting steam to the engine, or by any means sufiiciently reducing the pressure'in the generator, the flow of water to the same will be resumed.

Having thus described my invention, what I desire to secure by Letters Patent, is-

1. In a steam apparatus for propelling vehicles, the combination of the water tank, steam-generator, and steam-engine, and the fuel-burner, the steam-pipe leading from the generator to the engine being provided with a valved branch located between the generator and said valve in the main pipe, said branch being adapted to convey steam to the water-tank, substantially as set forth.

2. In a steam apparatus for propelling vehicles, the combination of the water-tank, steam-generator, and steam-engine, and the fuel-burner, the steam-pipe leading from the generator to the engine being provided with a valved branch located between the generator and said valve in the main pipe, said branch being adapted to convey steam to the watertank and through a conduit in the tank, and thence through a return branch to the main steam-pipe beyond the aforesaid valve in said pipe, and a valve in the main steam-pipe between the ends of the outgoing and returning branch pipes, substantially as set forth.

3. The combination of the steam-generator and steam-engine connected by a pipe or conduit, a cock in said pipe, a rod connecting said cock to a brake-rod, said rod extendingto the car-platform or like part of the car, and a brake and connections between it and said brake-rod, whereby the same rod can be manipulated to shut off steam and to apply a brake, substantially as set forth.

4. The combination of the steam-generator and steam-engine connected by a pipe or conduit, a valve in said pipe, a rod connecting said valve to a brake-rod, a fuel-supply pipe having a valve also connected to said brakerod, a brake and connections between it and said brake-rod, whereby the same rod can be manipulated to shut off both steam and fuel and to apply a brake, substantially as set forth.

5. The combination of a water-tank, generating-coil, and steamengine, the tank and generator communicating by an unobstructed water-supply pipe, and a steam-pipe leading from the generator through said water-tank to the engine, substantially as set forth.

6. The combination of awater-tank and gencrating-coil located on about the same level and communicating by an unobstructed pipe opening into the tank below the water-level, a burner, and means forautomatically reducing the fire, substantially as set forth.

7. The combination of a water-tank an d generating-coil located on or about the same level and communicating by an unobstructed pipe opening into the tank below the water-level,

a burner, and means for directing surplus steam to the tank to heat the same, substantially as set forth.

8. The method of generating steam, which consists in keeping an open communication between the water-tank and generator, conducting water into said generator, arresting the flow by back-pressure due to an increase of pressure above the normal or working pressure, and automatically reducing the fire to prevent excessive steampressure, substantially as set forth.

9. The method of generating steam, which consists in continuously conducting water into a steam-generator and conducting the surplus steam to the water-tank, and automatically controlling the generation of steam, substantially as set forth.

10. The combination of a generator composed of coiled pipe or equivalent, a watertank in open communication therewith, a steam-pipe having a cut-off cock, and an engine, substantially as set forth.

11. In a steam apparatus for propelling vehicles, the combination of the water-tank, steam-generator, and steam-engine, and the fuel-burner, the steam-pipe leading from the generator to the engine being provided with a valved branch located between the generator and said valve in the main pipe, said branch being adapted to convey steam to the water-tank, and a condenser whereby steam may be noiselessly condensed, substantially as set forth.

12. The combination of the brake mechanism and the fuel-supply pipe provided with a cock, both the brake and the cock being connected to and operated by a single device, such as a cranked rod and connecting devices, substantially as set forth.

13. The combination of the brake mechanism and the steam-supply pipe provided with a cock, both the brake and the cock being connected to and operated by a single device, such as a cranked rod and connecting devices, said device extending to the car-platform or the like and adapted to be operated therefrom to either close the cook or apply the brake or to release the brake and open the cock.

14. The combination of the brake mechanism, the oil-supply pipe and its cock, the steam-supply pipe audits cock, and the brake, all being connected to and operated by a single device,such as a cranked rod and connecting devices, substantially as set forth.

15. In combination with a street-car, the hot-water tank, the steam-coil or. generator, the pipe of the coil communicating with a pipe extending to an engine and provided with a valve or cook for controlling the steamsupply to the engine, the oil-tank provided with a pipe to convey oil to the burner and having a cock to controlthe flow of oil, steamengine, the steam-condensers, and a brake, the oil and steam cocks being controlled by a lever, which lever also operates the car-brake, substantially as set forth.

16. In combination with a street-car, the hot-water-pressure storage-tank, the coiledpipe generator, the fuel-supply tank and its pipe, the latter being provided with an automatically-regulated cut-off, and the burner, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

' WVILLIAM E. PRALL, J R.

WVitnesses:

BENJ. R. CATLIN, S. G. I-IoPKINs. 

